In general, network systems support a user's connection to a web server based on various kinds of networks. The network systems can be classified into wired network systems and wireless network systems according to the kinds of networks on which the network systems are based.
However, network systems providing web services are generally based on Transmission Control Protocol (TCP)/Internet Protocol (IP) regardless of the kinds of networks.
TCP and IP are communication protocols that are most generally used among the Internet protocol suite. The Internet protocol suite defines a set of communication protocols that nodes such as computers use to transmit/receive information on the Internet. The TCP is a protocol belonging to a transport layer in an Open System Internet (OSI) reference model, and the IP is a protocol belonging to a network layer in the OSI model.
The TCP/IP is applied in a wireless network as well as a wired network, in the same fashion. The IP can be classified into the case of using a fixed IP and the case of using a floating IP.
Most of network systems uses a Hypertext Transfer Protocol (HTTP) to connect to a web server. The HTTP is a request/response protocol that is executed between a client and a server in order to transmit/receive information on the web. The HTTP is a protocol belonging to an application layer in the OSI reference model.
For example, a web browser, which is a client, requests a server to send web pages or image information through the HTTP. The server provides the requested information to the web browser in response to the request from the web browser.
As a security-enhanced version of the HTTP, a Hypertext Transfer Protocol over Secure Socket Layer (HTTPS) has been developed for communication authentication and encryption. The HTTPS is widely used in electronic commerce.
The HTTPS encodes session data through a Secure Socket Layer (SSL) or Transport Layer Security (TLS) protocol, instead of using general text for socket communications. Accordingly, the HTTPS secures appropriate protection of data. For example, the standard TCP/IP port of the HTTPS is 443.
Generally, Uniform Resource Locators (URLs) of web pages using the HTTP start with “http://”, and URLs using the HTTPS start with “https://”.
FIG. 1 shows a procedure for calling a web page according to a request from User Equipment (UE) in a typical network system.
As shown in FIG. 1, the procedure for calling a web page according to a request from UE is composed of Domain Name System (DNS) transaction operation, TCP session establishment operation, and HTTP request/response operation.
In the DNS transaction operation, a web browser included in UE acquires an IP address from a DNS server. In the TCP session establishment operation, the web browser included in the UE establishes a TCP session with a specific web server for HTTP connection. In the HTTP request/response operation, the web browser included in the UE transmits and receives information to open a desired web page.
In the following description, although a main agent for specific operation is mentioned as UE, operation for opening a web page should be interpreted to be performed by a web browser being executed on UE.
In the procedure described above, in order for UE to open a desired web page, Round Trip Time (RTT) is generated at least three times. As shown in FIG. 1, Ta is generated one time, and Tc is generated two times. The Ta is RTT that is anticipated between the UE and the DNS server due to the DNS transaction operation, and the Tc is RTT that is anticipated between the UE and the web server due to the TCP session establishment operation or HTTP request/response operation. The Tc includes RTT that is anticipated between the UE and the proxy server, and RTT (that is, Tb) that is anticipated between the proxy server and the web server. Since the Tb is anticipated to be generated in both the TCP session establishment operation and the HTTP request/response operation, the procedure of calling the web page includes Tb two times.
Accordingly, the total T of RTT in a general procedure for calling a web page can be defined as “Ta+2*(Ta+Tb)”. For example, if each of “Ta” and “Tb” is assumed to be 100 ms, the total T of RTT will be 500 ms.
Accordingly, in order to increase a user's convenience, a method for reducing RTT that is generated in a general procedure for calling the web is needed.